Solder Paste Qualification Testing

Many SMT operations struggle with “process issues” that are actually solder paste-related, and have been resolved in newer generations of the materials. Nagging defects like tombstones, solder balls, excessive voids and Head-In-Pillow can often be mitigated with a change of solder paste. Newer formulations print better, wet better, endure hot reflow cycles better, and void less than older ones.

In the world of solder pastes, one size does not fit all, which is why there are so many variants to choose from. The myriad of options can be overwhelming, and matching the right product to any given operation can be confusing, time consuming and costly:

Solder paste has many conflicting properties – one that prints well may not pin test well, or one that minimizes voiding may reflow well, and tradeoffs must be considered

Developing test methods takes a great deal of engineering time and experience

Executing the tests requires engineering and production line time

Production boards are expensive test vehicles and may not test every property

Laboratory test boards often require a lot of manual setup and may not test every property, requiring multiple boards, setups and test runs

When a small EMS provider determined it was time to update the SMT process chemistry, they needed to develop a test program that they could execute efficiently while keeping production running and costs under control. When a solder paste provider wanted to commercialize their laboratory test board and needed a beta site, a working partnership was formed. The cooperative effort produced a consolidated test plan that gauges key solder paste properties, requires less than one shift of line time per product evaluated, and is available as a customizable, off-the-shelf kit.

This 90-minute webinar reviews the initial test plan, data collection and analysis processes, and presents the results of the original study. It discusses some of the issues encountered during test development and their resolutions or workarounds. It then interprets the findings using a scorecard method that helps the user weigh the importance of individual solder paste performance characteristics to their operation.

The webinar then details the process of turning the laboratory board that was beta tested into a production line-ready kit, based off the beta builds, including:

Updates to the PCB layout to improve sample sizes, embed DOEs and reduce cost

Full documentation on the PCB including placement and ODB++ files with included BOM for easy programming

An assembly configurator that calculates sample sizes and component costs as the user inputs the number of PCBs they want to print and populate

Stencil and PCB support designs

Step-by-step instructions on how to execute a test that evaluates 20+ solder paste properties in 30 prints and 4 hours of line time

The score card that enables the assembler to customize their selection criteria for their operation, understand the potential tradeoffs, and make a data-driven decision on their next process chemistry

Additional up-to-date information on the kit, such as availability and the status of the statistical reduction methods will also be provided, as the development work continues.

About the Presenters:Chrys Shea is the President of Shea Engineering Services, a consulting firm that produces technical studies and communications tools for the electronics manufacturing industry. Chrys is a frequent speaker at industry events, and has three times received the SMTAI “Best of Conference” award for her work on solder paste printing. In 2012 she was honored with the SMTA "Member of Technical Distinction" award. Chrys earned her B.S. in Mechanical Engineering from the University of Massachusetts and her M.S. in Manufacturing Engineering from the University of Rhode Island. She is a past president of the Philadelphia SMTA chapter, and sits on numerous IPC and SMTA technical committees. Chrys launched Shea Engineering Services in 2008.

Douglass Dixon is the Marketing Communications Director for Henkel Electronic Materials LLC and is responsible for managing all of the business unit’s global marketing communication activities. With over 20 years of electronics industry experience, Dixon has a broad skill set that includes engineering, field service, applications, product management and marketing communications expertise. Since joining Henkel in 2001, Dixon’s role has centered on strategic communications initiatives that have significantly raised the company’s profile within the global electronics market. During his tenure at Henkel, Dixon has also championed multiple service initiatives on behalf of the company that have made a positive impact on the communities in which Henkel Electronic Materials employees live and work. Examples include Henkel’s work with Think Together, a California-based organization dedicated to encouraging children to stay in school; and the Tianhua Orphan Education Project, a Chinese charity that provides full educational assistance for orphaned children. Dixon holds an Engineering degree from the University of Utah and, in his current role with Henkel, is based in the company’s Irvine, California facility.